1. Field of the Invention
The present invention relates generally to a horizontal, suspension or inclined cam unit, which can be combined with a set of metal mold tools as used for example, in bending selected edges or ends of a car body frame, and particularly to a cam slider to be used in such a cam unit.
2. Related Arts
A large-sized metal plate is formed into a desired car body shape by pressing the metal plate between a stationary metal mold tool and a movable metal mold tool both aligned vertically. Referring to FIG. 5, when it is desired that holes are made on selected sides of the pressed product or when it is desired that selected edges or ends of the pressed product are bent, a horizontal cam unit 1a is attached to the movable and stationary metal mold tools 20 and 24 to effect a required machining on the pressed product. The horizontal cam unit 1a comprises a cam drive 21 and a cam slider 22. The cam drive 21 has an oblique surface 21a formed on its end, and the cam slider 22 has an oblique surface 22a, also. The cam drive 21 is fixed to the upper movable metal mold tool 20, and the cam slider 22 is slidably fixed to the base 24 of the lower stationary metal mold tool with their oblique surfaces 21a and 22a laid on each other. The cam slider 22 has a machining tool 23 (for example, a drill) fixed to its vertical side.
In operation the movable metal mold tool 20 reciprocates up and down to move the cam slider 22 right and left, thereby performing a required machining on the side surface of the pressed product.
The cam slider 22 is spring-biased leftward all the time by a resilient body 26 such as a spring mounted to a guide pin 26, which is fixed to the stationary metal mold 24. Thus, the rising of the movable metal mold 20 and hence the cam drive 21 will permit the cam slider 22 to return to its original position.
Referring to FIGS. 6 and 7, a suspension cam unit comprises an upper cam holder 27, an intermediate cam slider 28 and a lower cam base 29, all of which are laid slidably on each other. The upper cam holder 27 is fixed to the upper movable metal mold tool, and can be raised and lowered vertically as indicated by a double-headed arrow S1. The raising and lowering of the upper cam holder 27 over the stroke S1 will cause the cam slider 28 to move different strokes S2 and S3 in predetermined directions as indicated by double-headed arrows S2 and S3. The lower cam base 29 is fixed to the stationary metal mold tool to allow the cam slider 28 to perform a required cam action.
In this example the cam holder 27 has a guide pin 31 fixed thereto whereas the cam slider 28 has a resilient member 30 contained in its recess. The resilient member 30 is supported by the guide pin 31 to apply a resilient force to the cam slider 28, thereby making the cam slider 28 to return to its original position after performing the required cam action.
As for the former horizontal cam unit of FIG. 5 the spring 26 is fitted on the spring guide pin 26a which is fixed to the base 24 of the stationary metal mold tool, and the spring 26 abuts the vertical side of the cam slide 22 to apply its resilient force to the cam slider 22.
When it is required that a machining tool is positioned horizontally (0 degrees) or at an inclined angle of 10 or 15 degrees to meet occasional demands dependent on the particular shapes of car bodies, the base 24 of the stationary metal mold tool needs to be so modified as to position the spring guide pin 26a and the spring 26 at an oblique angle as desired.
The base 24 is massive, and it costs much to make and store a number of massive objects each permitting a selected machining tool to be attached at a desired oblique angle. A large warehouse space is required for storing such massive articles. Also, it is necessary that guide pins 26a and springs 26 be kept in custody at a different place other than the warehouse in which the massive articles are stored. When used, a selected guide pin and associated spring need to be attached to the base 24 and the cam slider 22 in exactly correct positions. This requires a skillful and tedious work; if such resilient parts are fixed a minimum amount apart from the correct position, the cam slider cannot move smoothly.
The cam slider 22 has no resilient member equipped therewith for permitting it to automatically return to its original position, and therefore, such cam slider cannot be readily applied to a pressing metal mold tool for shaping car bodies or to any other inclined machining apparatus. Stated otherwise, such cam sliders are reserved for exclusive use, and therefore, they cannot be marketed as separate parts for non-exclusive use.
As for the latter suspension cam unit the cam holder 27 is designed to have a guide pin 31 fixed thereto, and therefore, the cam unit has same defects as described above.